How to Use the Command 'info' (with examples)
The info command is a powerful tool used in Unix-like operating systems for accessing documentation stored in the GNU Info format. This command is particularly valuable for users who need to navigate through detailed documentation hierarchically, starting from a top-level menu and exploring through various sub-menus and nodes. The info command provides a robust alternative to other documentation viewers like man by offering a more structured and comprehensive way of documentation access. With the info command, users can easily traverse through the documentation and find the information they need efficiently.
Use case 1: Start reading top-level directory menu
Code:
info
Motivation:
In Unix-like systems, accessing documentation is crucial for users who need to understand the functionalities of various programs and commands. The info command without additional arguments starts by displaying the top-level directory menu. This is particularly useful for users who are new to a system or looking to browse through available documentation systematically. By starting at the top-level directory, users can explore the structure of documentation and navigate to sections of interest with ease.
Explanation:
The command info by itself launches the info reader and presents the main menu, which acts as a directory to all available manuals. From this menu, users can select specific topics to dive deeper into, providing a guided way to navigate documentation.
Example output:
Upon executing the command, users will see a menu-like interface with a list of available documentation entries. Each entry corresponds to a set of instructions or supporting text files that detail various components or tools available within the system. Users can navigate through this menu to find specific documentation such as info gcc for the GCC Compiler documentation or info coreutils for GNU Core Utilities.
Use case 2: Start reading at given menu item node from top-level directory
Code:
info menu_item
Motivation:
When users have a specific topic in mind or need to access documentation directly related to a particular program, starting at a specific menu item can save significant time. Instead of navigating through potentially overwhelming top-level menus, this use case allows users to jump straight to the information they require, streamlining the search process and improving workflow efficiency.
Explanation:
The command info menu_item starts the info reader directly at the specified menu item node from the top-level directory. The menu_item argument is a placeholder for the name of the manual or topic users wish to access directly. By specifying this argument, users bypass the initial directory and jump straight to the documentation relevant to their query.
Example output:
Executing the command info gcc would skip the top-level menu and immediately present the GNU Compiler Collection (GCC) documentation. This output includes detailed information on GCC’s invocation, optimization options, and specific usage instructions that aid users in compiling programs efficiently.
Use case 3: Start reading at second menu item within the first menu item manual
Code:
info first_menu_item second_menu_item
Motivation:
For users who are familiar with the structure of the documentation or have specific sections of interest in mind, this command allows them to navigate directly to sub-sections within a manual. It is especially useful in extensive documentation where drilling down into sub-modules or sections is necessary to retrieve more granular information on a topic.
Explanation:
Here, info first_menu_item second_menu_item specifies that the info reader should open a sub-node (second_menu_item) within a parent node (first_menu_item) in the documentation hierarchy. This two-step navigation helps users access deeply nested information quickly without manually navigating through each level of the menu.
Example output:
Executing info gcc optimizations would take users directly to the ‘Optimizations’ section within the GCC documentation. The content under this node provides in-depth details about various compiler optimization flags and techniques that users can deploy to enhance the performance of compiled programs.
Conclusion:
The info command is an indispensable documentation tool in Unix-like systems, offering layered access to manuals and help texts. Whether users are browsing through documentation, looking for specific topics, or diving into detailed sections, knowing how to capitalize on the features of the info command can make documentation navigation an efficient and effective process. These use cases present practical scenarios for utilizing the info command, emphasizing its flexibility and utility across different documentation needs.
